Surveys of the nutritional status of hospitalized patients in the U.S. have revealed a high incidence of protein-calorie malnutrition. Our foregoing investigations have demonstrated that infusions of isotonic amino acid solutions (A3W) containing no dextrose are much more effective in preserving the Body Cell Mass than routine intravenous therapy with isotonic dextrose (D5W). Even more significant, clinically, is the fact that albumin levels tend to fall rapidly during therapy with D5W, which is associated with depression of cell mediated immunity, whereas during A3W therapy, the development of such a state of "visceral attrition" (resembling by certain features to Kwashiorkor) is effectively prevented. We have developed a concept for the regulation of energy and protein metabolism which explains the effectiveness of A3W therapy, as well as the disadvantages of D5W therapy. The latter interferes not only with the normal mobilization of fat stores, with the development of starvation ketosis, but also with the release of amino acids from muscle which should normally occur to support visceral protein synthesis. The aims of the proposed investigation are, in animal studies primarily, to elucidate the metabolic behavior following trauma or during sepsis. In studies on patients, further improvements intravenous and oral nutritional therapies are being sought, as well as the strengthening of the metabolic rationale on which they should be based.